Volition

Abstract

Volition is a type of mental process: the capacity to form intentions and to initiate and control action in their service, the psychological machinery of willing. This article distinguishes volition from the motivation that precedes it via the Rubicon model, then turns to the neuroscience that made it measurable: the readiness potential and Libet's finding that it precedes the reported urge to act by a few hundred milliseconds. It sets out the accumulator model that reinterprets the signal as averaged neural noise, and decoding studies that read a choice from the brain seconds early. It closes with the sense of agency, the neural signature of vetoing an action, and the disorders in which willing itself breaks down. Three demonstrations let the reader cross the Rubicon, run Libet's clock, and drive an accumulator to threshold.

Keywords: volition, readiness potential, intention, sense of agency, free will

A person deciding to raise a hand, and then raising it, performs something no reflex arc explains. The movement is not compelled by a stimulus, it serves a goal the person set, and it is accompanied by the compelling feeling of having brought it about oneself. Volition is the family of mental processes responsible for this: the forming of an intention, the initiation of the action that fulfils it, the control that keeps the action on course, and the experience of authorship that attends it (Haggard, 2008). It is the faculty the word will names in ordinary speech, and for most of psychology's history it was thought too subjective to study. The experimental turn came from an unlikely direction, electrophysiology, and it produced a result so counterintuitive about the timing of conscious will that the field has argued over its meaning ever since. This article traces volition from the motivational states that precede an action to the neural events that initiate it, and from the feeling of agency to the conditions in which willing fails.

What Volition Is

Volition is the process by which a person translates a goal into action: it selects an action, commits to performing it, initiates it at a chosen moment, and monitors and adjusts it until the goal is met. The defining mark of a volitional act is that it is endogenous rather than exogenous — generated from within, in the service of an internal goal, rather than triggered directly by an external stimulus. Raising a hand because one has decided to is volitional; jerking it back from a hot surface is not. This is not a sharp line but a dimension, and much of the interest of the subject lies in the middle of it, in acts that are neither pure reflex nor pure deliberation (Haggard, 2019).

Because willing is private, volition long resisted the experimental methods that served perception and memory, and it fell outside the scope of behaviourism entirely, which treated the internal act of will as either illusory or beyond study. Two developments brought it back. The first was conceptual: the recognition, within the study of motivation, that choosing a goal and pursuing it are distinct psychological states with different properties, which gave volition a definite place in the arc of an action rather than treating it as a single undifferentiated push. The second was methodological: the discovery that the preparation of a voluntary movement leaves a measurable electrical trace on the scalp, which turned the will from a philosophical topic into one with a dependent variable. The sections that follow take these in turn — first the motivational architecture that surrounds the volitional act, then the neuroscience that made it measurable.

Crossing the Rubicon: Motivation Versus Volition

The clearest way to locate volition is to mark where it begins. Heinz Heckhausen and Peter Gollwitzer proposed that an action episode passes through four phases divided by a decisive transition. In the predecisional phase the person deliberates, weighing the desirability and feasibility of competing goals; this is the province of motivation. The transition comes when the person forms a goal intention — commits to one goal — an act the model likens to Caesar crossing the Rubicon, after which deliberation is over and retreat is no longer entertained. The two postdecisional phases, preactional and actional, are the province of volition: here the person plans when and how to act, initiates the action, and sees it through, before a final postactional phase evaluates the result (Heckhausen & Gollwitzer, 1987).

The model's sharpest claim is that crossing the Rubicon changes the mind's whole cast, producing two distinct mindsets. The deliberative mindset that precedes the decision is even-handed and realistic: it samples information impartially and appraises the person's chances accurately, because a good decision requires it. The implemental mindset that follows is partial and optimistic: it closes down reconsideration, filters information for what serves the chosen goal, and inflates the person's sense of control, because these biases help get the action done. Heckhausen and Gollwitzer found that people induced into the two mindsets differed accordingly in what they attended to and remembered, evidence that commitment to a goal is not just a decision but a reconfiguration of cognition (Heckhausen & Gollwitzer, 1987). The first demonstration lets the reader move an action through the four phases and watch the governing mindset switch at the Rubicon.

Volition's central practical problem is the gap between intention and action: people form goal intentions they fail to enact. Gollwitzer's answer was the implementation intention, an if-then plan that specifies in advance the situation in which one will act and the action one will take — if situation X arises, then I will perform response Y. By committing to a concrete cue, the plan hands control of the action over to that cue, so that when the situation arises the action is initiated swiftly and without further deliberation, as though it had become automatic. Across many studies this simple planning device produces medium-to-large increases in the rate at which goals are actually attained, and it does so precisely by strengthening the volitional link between an intention and its execution rather than by strengthening the intention itself (Gollwitzer, 1999).

That an idea can itself set off the movement it represents is the oldest psychological account of how a volitional act gets started, the ideomotor principle. William James held that every representation of a movement tends to awaken that very movement unless a competing representation holds it back, so that to think of an act vividly and without rival is already to begin performing it — on this view the will adds no separate impulse beyond the idea of the deed itself (James, 1890). Contemporary work has revived and formalised the principle: actions are coded in terms of their sensory effects, so that calling an intended effect to mind retrieves and triggers the motor pattern that produces it, a mechanism now supported by a broad experimental literature on how perceiving or imagining an outcome primes the action that brings it about (Shin, Proctor, & Capaldi, 2010). The ideomotor principle supplies the mechanism the implemental phase needs: it is how a pre-committed cue can initiate an action without renewed deliberation, and why a well-formed if-then plan can feel automatic when its moment arrives.

The Readiness Potential and Libet's Experiment

The neuroscience of volition begins with an EEG signal. Recording the electrical activity preceding self-paced voluntary movements, Hans Kornhuber and Lüder Deecke discovered in the 1960s a slow negative potential that begins to build over the scalp roughly a second before the movement itself — the Bereitschaftspotential, or readiness potential (Kornhuber & Deecke, 1965). It arises from the supplementary motor area and related frontal regions, and its presence before a movement, but not before a passive or reflexive one, made it the electrophysiological signature of motor preparation: the brain visibly readying itself to act.

Benjamin Libet turned this signal into a probe of consciousness. If the readiness potential marks the brain preparing to move, when does the person become aware of the intention to move relative to it? Libet had participants make a simple flexion of the wrist whenever they felt the urge, with no external cue, while he recorded the readiness potential and the muscle onset. To timestamp the conscious intention, he used a revolving spot on a clock face and asked participants to report where the spot had been at the instant they first felt the wish to move — a subjective moment he labelled W. The result was startling. The readiness potential began about 550 milliseconds before the muscle moved, but the reported time of conscious intention, W, came only about 200 milliseconds before it. The brain's preparation to act thus preceded the person's awareness of deciding to act by roughly 350 milliseconds (Libet, Gleason, Wright, & Pearl, 1983). Figure 1 lays out this timeline and the interpretation that made it famous.

Libet read the finding as showing that the brain, not the conscious self, initiates a voluntary act: the readiness potential is already under way before the person knows they have decided, so the felt decision cannot be its first cause (Libet, 1985). The claim ignited a debate about free will that runs to the present, and it also drew immediate methodological fire, chiefly about whether the moment of a fleeting conscious urge can be timed against a moving clock with the precision the argument requires. The second demonstration reconstructs Libet's clock so the reader can see how W was measured and where the events fall.

Reinterpreting the Readiness Potential

The strong causal reading of Libet's result assumes the readiness potential is a specific command signal — a discrete event that begins when the brain commits to move. Aaron Schurger and colleagues challenged that assumption at its root. Spontaneous neural activity fluctuates continuously, and in Schurger's account a self-paced movement is triggered when this ongoing fluctuation, together with a slight drift, happens to cross a threshold. Because the readiness potential is computed by averaging EEG backward from the moment of movement, it necessarily selects those trials in which the fluctuating signal drifted upward into the threshold; averaging them time-locked to the crossing manufactures a smooth rising ramp even though no such ramp exists on any single trial. On this reading the readiness potential is not the trace of an early decision at all, but a statistical shadow cast by the way noisy accumulation is aligned to the movement it produces (Schurger, Sitt, & Dehaene, 2012).

The accumulator model reframes what Libet measured. If the moment of movement is set partly by random fluctuation crossing a threshold, then there is no hidden early decision for consciousness to lag behind; the readiness potential's head start over W loses its dramatic significance, because the potential reflects accumulating noise rather than an executed intention. The proposal does not resolve the free-will question so much as dissolve one version of it, and it has itself been scrutinised and refined: a subsequent review sets out what the readiness potential can and cannot be taken to show, and stresses that its interpretation still turns on assumptions about what the averaged signal represents (Schurger, Hu, Pak, & Roskies, 2021). The third demonstration lets the reader drive such an accumulator to threshold and see how averaging its threshold-aligned traces produces a readiness-potential-like curve.

A related qualification concerns the kind of decision Libet studied. His task asked for an arbitrary movement made for no reason at a moment of no consequence, and it is precisely such arbitrary, unmotivated choices that a noise-driven accumulator best describes. When Uri Maoz and colleagues compared arbitrary choices with deliberate ones that carried real stakes, a readiness potential preceded the arbitrary choices but was markedly reduced or absent before the deliberate ones, suggesting that the signal is a feature of picking without a reason rather than a universal precursor of all voluntary action (Maoz, Yaffe, Koch, & Mudrik, 2019). The generalisation from Libet's finger-flexions to weighty human decisions, on this evidence, does not go through cleanly.

The same body of evidence supports more than one account of what the readiness potential is, and the accounts differ chiefly in what they take the signal to represent and what they conclude about the timing of will. Table 1 sets them side by side.

Decoding Decisions Before Awareness

If Libet's electrode caught the brain preparing to move before awareness, later work extended the lead time dramatically and moved it forward in the brain. Using functional MRI and multivariate pattern analysis, Chun Siong Soon, John-Dylan Haynes and colleagues had participants freely decide to press a left or right button while the outcome of the decision was decoded from patterns of brain activity. The specific choice could be predicted above chance from activity in prefrontal and parietal cortex as much as seven to ten seconds before the participant reported consciously deciding — far earlier than the readiness potential, and involving regions that plausibly shape the content of the decision rather than merely its timing (Soon, Brass, Heinze, & Haynes, 2008). The prediction was well above chance but far from perfect, a point often lost in summaries: the early signal biases the coming choice rather than fixing it.

Single-neuron recording tightened the link between neural activity and the felt moment of decision. Itzhak Fried, Roy Mukamel and Gabriel Kreiman recorded directly from neurons in the human medial frontal cortex in patients implanted with electrodes for clinical reasons, during a Libet-style task. They found individual cells whose firing rate changed well before the reported urge to move, and the progressive change across a population of such cells could predict the impending decision, and its timing, with increasing accuracy as the moment of movement approached — a cellular counterpart to the readiness potential, recorded from inside the brain rather than over the scalp (Fried, Mukamel, & Kreiman, 2011). Together these findings establish that neural precursors of a simple decision exist and can be detected before the person is aware of having decided; what they do not settle, and what the accumulator model contests, is whether those precursors are a command already issued or the noisy run-up to a threshold not yet crossed.

The Sense of Agency and Conscious Will

Alongside the initiation of action stands the experience of it: the sense of agency, the feeling that one is the author of one's own actions and, through them, of events in the world. Daniel Wegner argued that this feeling is not a direct readout of the mechanism that causes an action but an inference the mind constructs after the fact. On his theory of apparent mental causation, a person feels they willed an act when three conditions hold: the thought of the act comes before the act (priority), fits the act (consistency), and is the only apparent cause (exclusivity). Because these are the ordinary cues of causation, the inference is usually right, but it can be manipulated: people can be led to feel authorship of movements they did not make, or to disown movements that were theirs, by controlling the pairing of thought and action (Wegner & Wheatley, 1999). The feeling of conscious will, on this account, is a construction that tracks authorship reliably without being identical to it.

The neuroscience of agency has found more direct correlates of the will than the introspective report Libet trusted. Patrick Haggard and Martin Eimer asked which brain signal actually covaries with the awareness of movement, and found that the early, general readiness potential did not track trial-to-trial variation in W, whereas the lateralized readiness potential — the later, side-specific signal that reflects the selection of a particular hand — did. Awareness of intending to move a specific limb is thus more closely tied to the neural specification of which movement to make than to the earliest, non-specific preparation (Haggard & Eimer, 1999). Haggard's broader programme has mapped agency onto phenomena such as intentional binding, the compression of perceived time between a voluntary action and its effect, giving the sense of agency an objective behavioural measure to complement the subjective one (Haggard, 2008).

Wegner's retrospective inference is not the only account of where the sense of agency comes from. Its main rival is the comparator, or forward-model, account, borrowed from the theory of motor control. When the brain issues a motor command it also generates an efference copy of that command, and a forward model uses the copy to predict the sensory consequences the movement should produce; when the predicted feedback matches the feedback that actually arrives, the action is registered as one's own, and the sense of agency follows from that match. On this view agency is computed predictively, from the motor system's own signals as the action unfolds, rather than inferred wholly after the fact from the coincidence of a thought and an outcome. The two accounts are now generally treated as complementary rather than exclusive: a low-level predictive signal generated while the movement is made, and a higher-level reconstructive judgement assembled around it, together fixing how strongly an action feels self-authored (Haggard, 2017).

Vetoing an Action: The Neuroscience of Self-Control

Even granting that the brain begins preparing an action before awareness, Libet held that consciousness retains a power of refusal: in the roughly 200 milliseconds between W and the movement, the person can abort the act. He called this the veto, and others have called it free won't — the idea that volitional control may lie less in initiating actions than in withholding them at the last moment. The veto is harder to study than initiation, because a vetoed action produces no movement to time against, but it converts the question of will into one about inhibition rather than instigation.

Marcel Brass and Patrick Haggard gave the veto a candidate neural substrate. Having participants prepare self-chosen actions but cancel a proportion of them at the last moment, they found that the dorsal fronto-median cortex was more active when an intended action was cancelled than when it was carried out, and its activity distinguished successful from unsuccessful inhibition, implicating this medial prefrontal region in the last-moment suppression of an intended act (Brass & Haggard, 2007). Self-control at the scale of everyday life was long described by a different metaphor: Roy Baumeister and colleagues proposed that acts of self-control draw on a limited, depletable resource, so that exerting willpower on one task leaves less available for the next — the ego-depletion effect (Baumeister, Bratslavsky, Muraven, & Tice, 1998). That model has since run into serious empirical trouble: a large preregistered replication across many laboratories found the depletion effect to be close to zero, making it a prominent casualty of psychology's replication crisis and a caution against treating willpower as a simple energy that runs down (Hagger et al., 2016).

Disorders of Volition

Volition can fail, and the ways it fails map onto the components the healthy process comprises. At one extreme is a poverty of willed action. In avolition, a negative symptom of schizophrenia, patients show a marked reduction in the initiation and persistence of goal-directed behaviour despite intact movement, as though the drive to translate goals into action were weakened. In the akinesia of Parkinson's disease, the initiation of self-generated movement is impaired while externally cued movement is relatively spared, dissociating endogenous from exogenous action at the level of the basal ganglia. At the other extreme is action without will: in anarchic hand (often called alien hand) syndrome, following damage to the medial frontal cortex or corpus callosum, a hand performs complex goal-directed acts — grasping objects, unbuttoning a shirt just buttoned — that the patient disowns and cannot inhibit, a striking dissociation between the machinery that generates action and the will that is supposed to govern it (Hallett, 2007). These syndromes show that volition is not a single faculty that is present or absent but a set of separable processes — initiation, inhibition, and the sense of ownership — each of which can break down on its own.

Worked Example

The accumulator model can be worked by hand, and the third demonstration reproduces the calculation. Model the neural activity preceding a self-paced movement as a quantity that starts at a baseline level and accumulates over time until it reaches a fixed threshold, at which point the movement is triggered. Suppose the baseline level is 0.20 and the threshold is 1.00, in arbitrary units, and that on average the activity drifts upward by 0.016 units in each 10-millisecond step.

The deterministic part of the model gives the expected time to move. The distance the activity must cover is the threshold minus the baseline, 1.00 − 0.20 = 0.80 units. At a drift of 0.016 units per step, reaching threshold takes 0.80 / 0.016 = 50 steps, and at 10 milliseconds per step that is 500 milliseconds — close to the observed onset of the readiness potential before movement. Now add the model's essential ingredient: on each step the activity also receives a random nudge up or down (the ongoing neural noise), so that any single trial wanders rather than climbing smoothly, and the exact step on which it first crosses the threshold varies from trial to trial. On a lucky run of upward nudges the crossing comes early; on an unlucky run it comes late.

The crucial move is what happens when many such noisy trials are averaged after aligning them to the moment of threshold crossing. Because the average is taken backward from the crossing, every trial in the average ends at the threshold, and the trials that reached it did so by drifting upward beforehand; the mean of these selectively upward-drifting tails is a smooth curve that rises gently and then steepens into the crossing — the shape of the readiness potential. The signal appears to ramp up over hundreds of milliseconds not because any single trial contained a slow rising command, but because averaging threshold-aligned noise produces a ramp by construction. This is the model's central claim reduced to arithmetic: the 500-millisecond deterministic run-up sets the scale, and the backward-averaging of noise supplies the classic waveform, without any early moment at which a decision was made.

Discussion

Volition is the topic on which cognitive psychology, philosophy, and neuroscience meet most directly, and the meeting has been productive precisely because a private faculty was given a public measure. The readiness potential turned the will into an experimental variable, and Libet's timing result forced the field to ask what the felt moment of decision could possibly be if the brain is already preparing to act before it (Libet et al., 1983; Haggard, 2019). Half a century on, the interpretive centre of gravity has shifted. The strong claim that the brain decides before the person does now looks to rest on a contestable assumption about what an averaged signal represents, and the accumulator model offers a deflationary alternative in which threshold-crossing noise, not an early command, sets the moment of an arbitrary act (Schurger et al., 2012; Schurger et al., 2021).

Two lessons survive the deflation. The first is that volition is not one thing: the deliberative and implemental mindsets, the initiation of action and its inhibition, the execution of a movement and the sense of having authored it, are separable processes with distinct signatures and distinct failures, as the disorders of will make plain (Heckhausen & Gollwitzer, 1987; Brass & Haggard, 2007; Hallett, 2007). The second is a methodological caution the field learned twice over — once from the debate about timing a fleeting urge against a clock, and again from the collapse of ego depletion under preregistered replication (Hagger et al., 2016). Both episodes show that on a subject as laden with intuition as the will, the interpretation of a result matters as much as the result, and that the strongest conclusions are the ones most in need of a second look. What began as a question about free will has become a research programme about the components of action, and it is the more durable for the change.

Common Misconceptions

Libet's experiment proved that free will is an illusion.

It did not, and the claim overstates what the data show. The strong reading depends on treating the readiness potential as an early decision signal, an assumption the accumulator model directly disputes by reinterpreting it as averaged neural noise; the finding also comes from arbitrary, inconsequential choices that may not generalise to deliberate ones (Schurger et al., 2012; Maoz et al., 2019).

The readiness potential is the brain's command to move.

The readiness potential is an average computed backward from the moment of movement, not a signal read from a single trial. Because averaging noisy accumulation time-locked to a threshold crossing manufactures a smooth ramp, the potential can appear even if no single trial contained a rising command (Schurger et al., 2021).

Willpower is a fixed fuel that runs down as it is used.

The ego-depletion model that popularised this metaphor has largely failed to replicate. A large preregistered multilab study found the effect to be near zero, so self-control is better understood through motivation, attention, and belief than as the draining of a limited energy (Hagger et al., 2016).

Glossary

Accumulator model.

An account in which a self-paced movement is triggered when spontaneously fluctuating neural activity, aided by a slight drift, crosses a threshold; it reinterprets the readiness potential as an artefact of averaging such noise backward from the movement.

Anarchic hand.

A syndrome, following medial frontal or callosal damage, in which a hand performs complex goal-directed acts that the patient disowns and cannot inhibit; a dissociation between action generation and the will meant to govern it.

Avolition.

A marked reduction in the initiation and persistence of goal-directed behaviour, a negative symptom of schizophrenia, occurring despite intact capacity for movement.

Comparator model.

An account of the sense of agency from motor control, in which a forward model uses an efference copy of a motor command to predict the action's sensory consequences; agency follows when the predicted feedback matches the actual feedback, contrasted with a purely retrospective inference.

Deliberative mindset.

The impartial, realistic cognitive orientation of the predecisional phase, in which a person samples information even-handedly and appraises feasibility accurately while choosing among goals.

Ego depletion.

The proposed effect whereby exerting self-control on one task reduces performance on a subsequent one, as if drawing on a limited resource; a large preregistered replication found the effect near zero.

Endogenous action.

Action generated from within in the service of an internal goal, rather than triggered directly by an external stimulus; the defining mark of a volitional act, contrasted with exogenous action.

Goal intention.

A commitment to attain a particular goal, formed when a person crosses the Rubicon from deliberation to implementation; distinguished from an implementation intention, which specifies how and when it will be pursued.

Ideomotor principle.

The classical principle, stated by William James, that the mere representation of a movement tends to produce that movement unless an antagonistic representation prevents it; the oldest account of how the idea of an action initiates the action.

Implemental mindset.

The partial, optimistic cognitive orientation of the postdecisional phases, which closes down reconsideration and filters information for what serves the chosen goal, aiding execution.

Implementation intention.

An if-then plan linking a specified situational cue to a specified response, which hands control of the action to the cue and reliably raises the rate at which goals are attained.

Intentional binding.

The compression of perceived time between a voluntary action and its outcome, used as an objective behavioural index of the sense of agency.

Readiness potential.

A slow negative EEG potential (the Bereitschaftspotential) arising over frontal motor areas and building up to a second before a self-paced voluntary movement; the electrophysiological signature of motor preparation.

Rubicon model.

Heckhausen and Gollwitzer's account of an action episode as four phases (predecisional, preactional, actional, postactional) divided by the forming of a goal intention, which separates motivation from volition.

Sense of agency.

The experience of being the author of one's own actions and, through them, of events in the world; partly reconstructed after the fact rather than read directly from the action's causes.

Veto.

The proposed capacity to abort an already-prepared action in the brief interval before it executes; also called free won't, and associated with the dorsal fronto-median cortex.

Volition.

The mental process of forming intentions and initiating and controlling voluntary action in their service; the psychological faculty ordinarily called the will.

W (time of conscious intention).

In Libet's paradigm, the moment a person reports first feeling the urge to move, timed against a revolving clock spot; found to follow the onset of the readiness potential.

Key Researchers

Marcel Brass. Einstein Professor of Social Intelligence at Humboldt University of Berlin (formerly Ghent University); with Haggard he identified the dorsal fronto-median cortex as engaged when people cancel an intended action, giving the last-moment veto a candidate neural signature. Faculty Page - Google Scholar - ORCID

Peter M. Gollwitzer. Professor of Psychology at New York University and the University of Konstanz; with Heinz Heckhausen he developed the Rubicon model of action phases and introduced implementation intentions, if-then plans that strengthen the link between an intention and its execution. Faculty Page - Google Scholar - Wikipedia - ORCID

Patrick Haggard. Professor at the Institute of Cognitive Neuroscience, University College London; he has mapped the cognitive neuroscience of voluntary action and the sense of agency, including intentional binding and the tie between the lateralized readiness potential and awareness of movement. Faculty Page - Google Scholar - Wikipedia - ORCID

John-Dylan Haynes. Professor at the Bernstein Center for Computational Neuroscience and Charite - Universitatsmedizin Berlin; he applied multivariate pattern analysis to fMRI and showed that the outcome of a free decision can be decoded from prefrontal and parietal activity seconds before it reaches awareness. Faculty Page - Google Scholar - Wikipedia - ORCID

Benjamin Libet (1916-2007). Researcher in the Department of Physiology at the University of California, San Francisco; he timed the conscious intention to move against the onset of the readiness potential, launching the modern experimental study of volition and the debate over its bearing on free will. Wikipedia - Wikidata

Aaron Schurger. Assistant Professor at Chapman University (formerly INSERM/NeuroSpin, Paris); he proposed the stochastic accumulator model, reinterpreting the readiness potential as averaged spontaneous neural noise time-locked to movement rather than the trace of an early decision. Faculty Page - Google Scholar - ORCID

Daniel M. Wegner (1948-2013). Late John Lindsley Professor of Psychology at Harvard University; he proposed the theory of apparent mental causation and the illusion of conscious will, arguing that the feeling of willing an act is inferred from the reliable pairing of a prior thought with the action. Faculty Page - Wikipedia - Wikidata

Frequently Asked Questions

What is volition in psychology?
Volition is the mental process of forming intentions and initiating and controlling voluntary action in their service. It is the faculty ordinarily called the will, and it covers selecting an action, committing to it, starting it at a chosen moment, and monitoring it to completion (Haggard, 2019).

How is volition different from motivation?
Motivation is about choosing which goal to pursue; volition is about carrying the chosen goal out. The Rubicon model marks the boundary at the forming of a goal intention, after which a deliberative mindset gives way to an implemental one focused on execution (Heckhausen & Gollwitzer, 1987).

What was Libet's experiment?
Libet had people flex a wrist whenever they felt the urge, and timed that urge against a revolving clock spot while recording brain and muscle activity. The readiness potential began about 550 milliseconds before the movement, but the reported urge came only about 200 milliseconds before it, so brain preparation preceded awareness (Libet et al., 1983).

Does the readiness potential prove there is no free will?
No. The strong reading treats the readiness potential as an early decision signal, but the accumulator model reinterprets it as averaged neural noise, and the effect is clearest for arbitrary rather than deliberate choices, so the finding does not settle the free-will question (Schurger et al., 2012; Maoz et al., 2019).

Can brain activity predict a decision before a person is aware of it?
To a degree. Using fMRI, the outcome of a simple free choice could be decoded from prefrontal and parietal cortex up to about seven to ten seconds before the reported decision, though the prediction was above chance rather than certain, biasing the choice rather than fixing it (Soon et al., 2008).

What is the sense of agency?
The sense of agency is the feeling of being the author of one's own actions. Wegner argued it is inferred after the fact from cues that a prior thought preceded, matched, and seemed the only cause of the action, which is why it can be experimentally induced or disrupted (Wegner & Wheatley, 1999).

Is willpower a limited resource that gets used up?
Probably not in the way the popular metaphor suggests. The ego-depletion model claimed self-control draws on a depletable resource, but a large preregistered multilab replication found the effect close to zero (Hagger et al., 2016).

What happens to volition in brain disorders?
Volition can fail in separable ways: avolition in schizophrenia weakens the initiation of goal-directed action, Parkinsonian akinesia impairs self-generated movement, and anarchic hand syndrome produces goal-directed acts the patient disowns and cannot inhibit (Hallett, 2007).

References